Style sheets are pretty easy to learn. I have a couple of articles posted in the CSS section that will get you started.
The hardest part is memorizing which properties do what and which attributes go with them. I use this site as a memory tickler: http://www.eskimo.com/~bloo/indexdot/css/propindex/all.htm
Also, I don't know what class you are taking but the (free!) courses on this site are pretty good: http://www.w3schools.com/